1. Field of the Invention
The present invention relates to a mold set used for manufacturing an optical element, such as a lens, prism, or mirror, and to a manufacturing method for manufacturing an optical element.
2. Description of the Related Art
Conventionally, press molding has been performed in which apiece of glass which has been heated and softened is pressurized. When press molding is applied to a piece of glass, a molding set provided with a pair of molds and a sleeve which guides the pair of molds is used (see, for example, patent document 1).
In press molding, a piece of glass is heated to a glass-transition temperature or higher so as to be heated and softened, and it is pressurized and transformed by a mold and cooled down to the glass-transition temperature or lower so that it hardens and shrinks. A glass mold-object is then released from the mold and taken out as an optical element.    Patent Document 1: Japanese Laid-open Patent Publication No. H02-111635